Most internal combustion engines need extra fuel in the fuel system for what is generally termed "cold-starting". Automatic, heat-controlled chokes are used on many vehicle engines. This "choking" consists of blocking the air intake passage to the extent that the vacuum created by the movement of the engine pistons will be higher than normal in the fuel and air mixing passage and thus pull an extra quantity of fuel from the carburetor supply ports into the engine cylinders. After the engine has started and heat is developed in the area of the automatic choke, there will be an automatic release of the choke to allow normal air flow into the mixing passage.
With some small engines such as used on snowmobiles and outboard motors, an extra quantity of fuel is forced into the engine by a manual priming apparatus. This may facilitate the unitial starting but may not provide sufficient fuel to keep the engine running until it warms to the point that it can proceed to operate under normal carburetor conditions. Examples of priming systems operated manually are found in the Turner U.S. Pat. No. 3,371,658 (Mar. 5, 1968), O'Connor U.S. Pat. No. 3,983,857 (Oct. 5, 1976) and DuBois U.S. Pat. No. 4,309,968 (Jan. 12, 1982).
The present invention has the object of providing a manual, or remote controlled, priming system which can provide adequate supplemental fuel for initial starting but will also provide a prolonged or secondary supply of fuel to enable the engine to be fully warmed up before the secondary supply is discontinued and the normal carburetor functions begin. With outboard motors in particular, an operator may wish to get his craft underway as soon as the engine is started but it may stall shortly after starting unless a means is provided to supplement the fuel supply for a period after starting.
It is, therefore, an object to provide a carburetor with an integral body portion which houses a fuel supply to be injected into the engine for initial starting and which can receive replenishment fuel from the basic carburetor. It is a further object to provide a fuel supply system which utilizes the basic carburetor both for the initial injected starting charge but also for the supplemental secondary warm-up period. It is a further object to provide a starting system which is self-filling and which reduces itself after a start so that strenuous and repeated starting pulls are avoided. Another object and feature lies in the starting system which closes automatically after initiation to prevent fuel from being pulled from it into the enginne under normal operating conditions.
Another object lies in the adoptability of the system either to manual, at the carburetor position, or to remote power control from a cowl separated from the engine and carburetor.
Other objects of the invention will be apparent in the following description and claims in which the invention is described together with the manner and process of using it as directed to persons skilled in the art to enable use and practice of the invention, all in connection with the best mode presently contemplated for the invention.